Power source



32- P. Tmz 1,839,451

POWER SOURCE Filed Dec. 29, 1937 INVENTOR PAUL TAETZ TORNEY PatentedJan. 5,1932

UNITED STATES PAUL TATZ, 0F BERLIN, GERMANY, ASSIGNOR TQ GES ELLSCHAFTFUR DRAHTLOSE TELEGRAPHIE M. B. 11., OF BERLIN, GERMANY, A CORPORATIONOF GERMANY POWER SOURCE Application filed December 29, 1927, Serial No.243,259, and in Germany February 18, 1927.

The necessity of providing calling devices becomes more and more felt inproportion as radio frequency intelligence transmission means andmethods become more popular. Among the various methods adapted toeffecta radio frequency call the one appears most reliable in practicein which the calling transmitters when sending out a call are modulatedwith a suitable alternating frequency seeing that in this case thealtternating frequency amplifier means provided at most receiverapparatus can be used for extending the calling range for the call.

An object of the present invention is to disclose ways and means inconnection with this calling method adapted to realize considerablesavings in the production of the calling frequency.

Other objects of the invention will be evident from the followingdescription in connection with the drawings in which Fig. 1 represents apreferred embodiment of my invention in which the calling frequency istaken off in shunt relation, and

Fig. 2 shows another embodiment in which the calling frequency is takenoff in series relation.

According to the idea underlying this invention, the call (modulation)frequency is derived directly from the direct current service machinesproviding currentfor the filament and the plate, the calling frequencyconsisting of the commutation frequency (commutator ripples) of thesedirect current machines. The call frequency may be taken from themachines, as shown in Fig. 1, either in shunt relation to the terminalsof generator G, or else, as illustrated in Fig. 2, in series relationwith the main service current. T are required which are markedly biasedby the preponderant direct current component of the service current, andthis is attended with difliculties. Another inconven- In this latterscheme, transformers ience is that in this circuit arrangement, thetransformer must be adapted to the large service currents. V

For this reason, it is recommendable to derive the call frequency inshunt across the generator terminals, if possible, by way of a condenserC, Fig. 1 from the working potential.

In order to purify the call frequency, filter circuits S may be used inaddition.

The call frequency, generally speaking, needs to be of only limitedenergy since the transmitters are mostly furnished with input amplifiersand modulating means, for which reason energy being only of an order ofmagnitude equalling the normal control energy (microphone energy) isrequired. Otherwise the modulation frequency may be convenientlyamplified.

H avingthus described my invention what I desire to protect by LettersPatent is as follows:

1. In an arrangement for audio frequency modulation of radio frequencytransmitters, a source of direct current for energizing saidtransmitters said source having alternating current components, andmeans for utilizing the alternating current components on said directcurrent for modulating said transmitters.

2. A method of deriving modulating energy from existing transmittingstation equipments which comprises filtering out and utilizing thecommutator ripples in the existing direct current supply generators.

3. In a system for modulating radio frequency transmitter circuits withaudio frequency energy, means for deriving said audio frequency energycomprising a circuit coupled to the direct current generators of thetransmitter power supply system said circuit being adapted to transferfrom said generators to said modulating system any alternating currentenergy component present in said generator circuit.

circuit.

PAUL TATZ.

